This invention relates to photoelectric cells and collectors for transforming radiation energy into electrical energy. More particularly, it relates to the use of semiconducting monocrystalline elements with solid filled collectors of the total internal reflectance type for collection and utilization of radiant energy from solar and other sources.
Photoelectric cells are used for transforming radiation energy into electrical energy. The incident photons are absorbed in the semiconductor where they produce minority charge carriers, either holes or electrons, which diffuse to a charge separating junction, typically near the illuminated surface of the photoelectric cell, and make possible a delivery of electricity by the cell.
Generally, photoelectric cells consist of semiconductor wafers of various shapes. These semiconductor wafers are reduced to a desired final thickness by sawing, etching, and lapping with an accompanying loss of typically about one-half of the semiconductor material. However, the thickness of conventional semiconductor wafers cannot be reduced without limit because the photoelectric cell response will be reduced and, because the semiconductor materials are very brittle, the wafers break easily during manufacture and use unless proper thermal and physical conditions are maintained.
The phototelectric cell can be used with a collector to increase the amount of solar radiation reaching the surface of the cell, thereby increasing its effectiveness and electrical output. Many types and shapes of collectors, such as flat and curved mirrors, dished reflectors, fresnel lenses, and various trough shaped reflectors, have been used to concentrate sunlight upon a photoelectric cell. However, the problems inherent in efficient utilization of solar energy and the required intricate and costly apparatus for tracking the sun in its apparent daily motion through the heavens have not been adequately resolved by these devices.